HP-UX 11i v2 Installation and Update Guide, June 2006

Known Problems and Troubleshooting
Known Install and Update Problems
Appendix A 149
System Hangs After
Issuing Large I/O (>512 KB
in size) to Fibre Channel
Devices
System hangs may be experienced after issuing large I/O
(>512 KB in size) directly to physical disks accessed by a
single port Fibre Channel adapter (product number A6795A
or A5158A, claimed by the td driver).
I/O through file systems and/or logical volumes will not
issue such a large I/O. But LVM operations, for example,
lvextend and lvremove, performed on a volume group with
a large number of disks may issue large I/O for updating
LVM metadata on the physical disks. A fix will be provided
at a later date.
What To Do
A workaround is available which basically limits the
maximum I/O to a Fibre Channel device to 512 KB. But
some performance degradation may result from this
workaround. Contact HP Support to discuss the problem.
HP Does Not Recommend
Combining Root ("/") and
Boot ("/stand") Directories
When creating a custom file system configuration that
utilizes volume management, having the root ("/") and boot
("/stand") directories on the same partition is not
recommended. Default configurations have root and boot
directories in separate partitions when volume
management is active.
What To Do
The preferred approach is to use the default file system
configuration when installing HP-UX. If you chose to create
a custom file system configuration utilizing volume
management, make sure that root and boot directories are
on separate partitions.
Table A-1 Known Install and Update Problems (Continued)
Problem Description/Action